One-sided and two-sided context in formal grammars

Two-sided context specifications in formal grammars

In a recent paper (M. Barash, A. Okhotin, “An extension of context-free grammars with one-sided context specifications”, Inform. Comput., 2014), the authors introduced an extension of the context-free grammars equipped with an operator for referring to the left context of the substring being defined. This paper proposes a more general model, in which context specifications may be two-sided, tha...

One - sided Versus Two - sided Error in

A note on one-sided context-sensitive grammars

In this note it is proved that so called one-sided context-sensitive grammars can generate languages which cannot be generated by any context-free grammar. This fact is not quite new. It has been proved in [3], [4] and [5] (as far as the author knows). In [3] it is proved that a special one-sided context-sensitive grammar suggested by Dr. Fris ([1]) generates a language {a m b'"c"; Hn^ m} which...

One-sided Logic in Two-sided Markets

In this paper, I consider eight basic fallacies that can arise from using conventional wisdom from one-sided markets in two-sided market settings. These fallacies are illustrated using statements made in the context of regulatory investigations into credit card schemes in Australia and the United Kingdom. I discuss how these fallacies may be reconciled by proper use of a two-sided market analys...

Grammars with two-sided contexts

In a recent paper (M. Barash, A. Okhotin, “Defining contexts in context-free grammars”, LATA 2012), the authors introduced an extension of the context-free grammars equipped with an operator for referring to the left context of the substring being defined. This paper proposes a more general model, in which context specifications may be two-sided, that is, both the left and the right contexts ca...